Wireless Power Transmitter Frequency Scanning for Foreign Object Detection
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Solution Overview
Problem
Existing wireless power transfer systems face challenges in safely and efficiently transferring power due to the risk of foreign objects absorbing power, which can lead to hazards such as fires, and they lack effective detection mechanisms for chargeable devices and foreign objects.
Innovation Solution
A wireless power transfer system that includes a transmitter and a controller capable of scanning a frequency range to detect chargeable devices and foreign objects, transitioning between active and sleep modes based on detections to prevent power transfer to foreign objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If wireless power transfer is implemented to eliminate electrical cords, then safety hazards and clutter are reduced, but the risk of foreign objects absorbing power and creating fire hazards increases
Solution Approach 1:
The system performs frequency range scanning and foreign object detection before initiating full power transfer. The transmitter scans a frequency range to identify the presence of foreign objects or chargeable devices, determines detections based on the scan results, and only transitions to active power transfer mode when no foreign objects are detected, thereby preventing fire hazards before they can occur
Solution Approach 2:
The system continuously monitors the frequency range during operation and transitions between active and sleep modes based on detection results. When foreign objects are detected during scanning or operation, the system provides feedback to stop or prevent power transfer, creating a closed-loop safety mechanism that dynamically adjusts power transfer based on real-time detection
2Reliability
If frequency range scanning is performed to detect foreign objects, then safety is improved, but system complexity and detection time increase
Solution Approach 1:
The frequency scanning mechanism serves multiple functions: it detects foreign objects, identifies chargeable devices, determines optimal transfer frequencies, and monitors system status. The same scanning infrastructure is used for both safety detection and operational optimization, reducing the need for separate dedicated detection hardware and simplifying the overall system architecture
Solution Approach 2:
The system varies the frequency parameter during scanning to detect different types of objects and optimize power transfer. By changing the operating frequency across a range, the system can identify resonant frequencies of chargeable devices and detect foreign objects with different electromagnetic properties, enabling versatile detection with a single adjustable parameter rather than multiple fixed-frequency sensors
3Reliability
If continuous monitoring is performed to prevent power transfer to foreign objects, then safety is enhanced, but energy consumption increases
Solution Approach 1:
The system performs frequency range scanning periodically rather than continuously, transitioning between active scanning and sleep modes based on operational state. Scanning is performed at key moments such as when power transfer is initiated, when devices are placed on the charging surface, or at scheduled intervals during operation, reducing energy consumption while maintaining adequate safety monitoring
Solution Approach 2:
The monitoring intensity dynamically adjusts based on system state. The system performs comprehensive frequency scanning when transitioning to active power transfer, reduces monitoring during stable operation, and intensifies scanning when changes are detected such as new objects being placed on the surface. The controller adapts the scanning frequency and depth to match the operational context, optimizing the balance between safety and energy consumption
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively reduces the risk of power transfer to foreign objects by intelligently scanning and detecting chargeable devices, enhancing safety and efficiency in wireless power transfer operations.
Implementation Method 1
various devices may be charged, such as personal laptop computers, tablet devices, and smartphones... large coils radiating power to charge a number of these devices
Implementation Method 2
causing the transmitter coil to scan a frequency range that includes a maximum frequency and a minimum frequency. The operations include determining one or more detections based at least on the scan of the frequency range
Data Source
AI summary
A system, a circuit, and a method of wireless power transfer using a transmitter and a controller coupled to the transmitter. The controller is configured to perform operations including causing the transmitter to scan a frequency range that includes a maximum frequency and a minimum frequency. The operations further include determining one or more detections based at least on the scan of the frequency range. The detection may include a presence of one or more receivers, an absence of one or more receivers, and/or a presence of a foreign object. The operations include determining one or more further operations based on the one or more detections.